This invention relates to processes to catalytically hydrogenate hydrocarbon feedstocks with shaped, extruded hydroprocessing catalysts.
A number of catalyst shapes have been described in the prior art. U.S. Pat. No. 2,408,164 to Foster discloses catalyst shapes including solid and hollow cylinders, elongated star shapes, cylinders with corrugated edges, etc. Similar shapes are also shown in U.S. Pat. No. 3,997,426 to Montagna et al. U.S. Pat. No. 3,966,644 and U.S. Pat. No. RE. 30,155 issued to Gustafson disclose trilobal catalysts for hydrocarbon conversion. U.S. Pat. Nos. 3,674,680 and 3,764,565 to Hoekstra and Jacobs disclose catalyst shapes designed to eliminate catalytic material more than 0.015 inch from the catalyst surface and give surface area to volume ratios of between 100 and 250 inch.sup.-1. U.S. Pat. No. 3,347,798 to Baer et al discloses the production of hollow bead catalysts. U.S. Pat. No. 3,957,627 discloses spherical catalysts having a void center and a hole extending to the external surface. U.S. Pat. Nos. 4,116,819 and 4,133,777 disclose catalysts in the shape of elongated extrudates having alternating longitudinal grooves and protrusions on the surface.
The purpose of shaped catalysts has been to increase surface-to-volume ratio over conventional shapes, such as round cylinders and spheres to increase effective diffusion and increase metals loadings. Surface-to-volume ratios can be increased by reducing the size of the particles, but beds of such particles tend to have unacceptably high pressure drops across the bed.
This invention provides a process for hydroprocessing hydrocarbonaceous feedstocks, comprising contacting the feedstock with hydrogen under hydroprocessing conditions with porous catalyst particles, said particles:
(a) comprising between 2 and 25 weight percent of a catalytic metal from Group VIB and between 0 and 15 weight percent of a catalytic metal from Group VIII, where said weight percent is based on the catalytic metals content, calculated as reduced metals, of the total particle weight, supported on a refractory inorganic oxide; and
(b) being elongated extrudates having a cross-section which is oval with at least one bump thereon, said cross-section being capable of being circumscribed by a rectangle having a first dimension between about 0.060 and 0.125 inch and a second dimension, perpendicular to said first dimension, between about 0.030 and 0.100 inch, the ratio of said first dimension to said second dimension being between 1.3:1 and 3:1.